P040 Obstructive sleep apnea during REM sleep: Effects on morning and evening blood pressure

STUDY OBJECTIVES: Obstructive sleep apnea (OSA) is linked to the emergence and progression of cardiovascular complications including hypertension, stroke, arrhythmias, coronary artery disease and heart failure. Epidemiological studies have reported that hypertension is associated with respiratory events during REM sleep. We examined the relationship between respiratory events during REM and morning and evening hypertension in a clinical sleep population. METHODS: This study included data from in-laboratory diagnostic polysomnographic studies (n=797) from adults attending for investigation of OSA. Hypertension was defined using blood pressure measurements taken in the evening before and morning after polysomnography, and use of anti-hypertensive medication. Regression modelling was undertaken to examine the probability of evening and morning hypertension according to REM apnea hypopnea index (AHI), NREM AHI, gender, age, body mass index (BMI), alcohol use, total sleep time (TST), sleep time SpO2 <90%, smoking and waist-to-hip ratio. RESULTS: The probability of morning hypertension was significantly independently associated with age (p<0.001), BMI (p<0.001) and REM AHI (p=0.012). No significant effect was found for male gender, NREM AHI, alcohol use, TST, sleep time SpO2 <90%, smoking or waist-to-hip ratio (p>0.05 for all). The probability of evening hypertension was only significantly associated with age (p<0.001), BMI (p<0.001) and TST (p=0.029). CONCLUSIONS: Respiratory events during REM sleep are significantly associated with morning hypertension. Future research is needed to determine whether treatment of these events can prevent or reverse morning hypertension.